The Deterioration oe Manures. 
27 
salt in the manure but because there had not been enough rain to wash 
out the potash during the first year. The above figures represent 
a loss of 43.7 percent of the potash, 22.6 percent of the phosphoric 
acid and 38.0 percent of the nitrogen, which correspond closely to the 
results obtained under humid conditions. 
Potash and Phosphoric Acid. 
Since the potash salts and the phosphates are among the soluble 
salts, we find they are among those lost by leaching. It was pointed 
out that the phosphoric acid in the sheep manure was lost at about the 
same rate that leaching occurred. This seems to be the case here as 
the phosphoric acid determinations run very close together with the ex¬ 
ception of No. 4, which is probably high on account of the heavy ration 
of corn and alfalfa these cattle received. The potash determinations 
vary to a greater extent than those of the phosphoric acid, but to 
what this is due is a question. The cattle manures are much more un¬ 
satisfactory than the sheep manures, because so many different combi¬ 
nations of hays and grains fed are represented. The rich feed gives a 
manure rich in plant food, and this difference sometimes persists after 
years of weathering. The phosphoric acid and nitrogen are less than 
results given in the standard analysis, while the potash is much higher. 
This again emphasizes what has been said regarding the loss of pot¬ 
ash from sheep manure, and corroborates the statement that the 
heaviest loss under our conditions is not potash but nitrogen. The 
average of 13 potash determinations is 4.64 percent, more than 
twice the percentage in the standard analysis. 
There is, of course, an absolute loss of potash as the manure loses 
in weight through weathering. This loss probably begins at about the 
same time it did in the sheep manure, namely, after the first year, and 
from that time on, like the phosphoric acid, it is lost at about the same 
rate as the manure loses in weight. 
The Nitrogen. , 
The total nitrogen is lower than in the standard analysis. The aver¬ 
age of Table IV is 1.43 percent, while the standard analysis gives 2.24 
percent. The standard analysis is composed of very much 
younger manures than those in Table No. IV, and it will be noticed 
that the only manure in the table, No. 8, havijng an 
amount of total nitrogen equal to the standard analysis, is but six 
months old. Since the total nitrogen is low compared with the 
standard analysis, the absolute loss must be very large. The loss of 
nitrogen on air-drying the samples follows closely the lesults as given 
under the sheep manures, i. e., the loss is heaviest where there is the 
most free ammonia. There are some results in which an apparent gain is 
/ 
